Active energy transport and the role of symmetry breaking in microscopic power grids

We study the transfer of energy through a network of coupled oscillators, which represents a minimal microscopic power grid connecting multiple active quantum machines. We evaluate the resulting energy currents in the macroscopic, thermal, and quantum regime and describe how transport is affected by the competition between coherent and incoherent processes and nonlinear saturation effects. Specifically, we show that the transfer of energy through such networks is strongly influenced by a nonequilibrium phase transition between a noise-dominated and a coherent transport regime. This transition is associated with the formation and breaking of spatial symmetries and is identified as a generic feature of active networks. Therefore, these findings have important practical consequences for the distribution of energy over coherent microwave, optical, or phononic channels, in particular close to or at the quantum limit.